Nationally, about 11% of the total U.S. cotton crop is destroyed each year by hail. An insurance company is studying cotton hail-damage claims in Lubbock County. A random sample of 16 claims gave a sample mean of x = 12.5%. Let x be a random variable that represents the percentage of cotton crop in Lubbock County lost to hail. Assume that x has a normal distribution and o = 5.0%. Do these data indicate that they percentage of cotton crop lost to hail in Lubbock County is different (either way) from the national mean of 11%? Use alpha = .01 %3D

1. Tim Hortons wanted to estimate the difference in the mean amounts of caffeine in two brands of coffee. They took a sample of 18-lbs jars of Brand I and another sample of 13-lbs jars of Brand II coffee. The following summary data (sample statistics) are collected? nį = 10 x, = 23 S1 = 3 Brand I Brand II n2 = 12 x2 = 25 S2 = 4 Assume that the two populations are normally distributed. A. Test at 5 % level of significance, whether there is a difference in the mean amounts of caffeine between the 2 brands of coffee. B. Construct a 95% Confidence Interval to estimate the difference in the mean amounts of caffeine in 2 brands of coffee. C. Does the result in part b) confirm your findings from part a)?

The following information is available for two samples selected from independent normally distributed populations.   Population​ A:    n1=30    S2/1=25   Population​ B:    n2=30    S2/2=36     a. Which sample variance do you place in the numerator of FSTAT​?   b. What is the value of FSTAT​?

A company produces scooters used by small businesses that find them convenient for making short deliveries. The company is notified whenever a scooter breaks down, and the problem is classified as being either mechanical or electrical. The company then matches the scooter to the plant where it was assembled. The data table to the right contains a random sample of 200 breakdowns. Use the data file and the relative frequency assessment method to complete parts a through c. Electrical Mechanical Total Plant 1 21 52 73 Plant 2 74 53 127 Total 95 105 200 a. What is the probability a scooter was assembled at Plant 2? P(Plant 2) = (Type an integer or a decimal.) b. What is the probability that a scooter breakdown was due to a mechanical problem? P(mechanical) =D(Type an integer or a decimal.) c. What is the probability that a scooter breakdown was due to an electrical problem and the scooter was assembled at Plant 2? P(electrical and Plant 2) = (Type an integer or a decimal.)

The accompanying data are x = advertising share and y = market share for a particular brand of soft drink during 10 randomly selected years. x 0.104 0.072 0.072 0.077 0.086 0.047 0.060 0.050 0.070 0.052 y 0.137 0.127 0.120 0.086 0.079 0.076 0.065 0.059 0.051 0.039   b)Calculate the equation of the estimated regression line. (Round your answers to four decimal places.)   d)Calculate a point estimate of ?e. (Round your answer to five decimal places.)

A recent Gallup Poll interviewed a random sample of 1523 adults. Of these, 868 bought a lottery tickets in the past year. Suppose that in fact (unknown to Gallup) exactly 60% of all adults bought a lottery ticket in the past year. If Gallup took many simple random samples of 1,523 people, the sample proportion who bought a ticket would vary from sample to sample. The sampling distribution would be close to normal with a mean of 0.6 and a standard deviation of___ A)0.4899 B)0.0251 C)0.00016 D)0.0126

3.  Can SAT scores predict college performance?  Let x be a variable that represents SAT score of a computer science major, and let y be a variable that represents a student’s GPA upon graduation.  A random sample of n =15 computer science majors provided their SAT scores and GPAs: x 1232 1070 1086 1287 1130 1048 1121 1095 1135 1208 1333 1160 1186 1243 1261 y 3.52 2.91 2.4 3.47 3.47 2.37 2.4 2.24 3.02 3.32 3.59 2.54 3.19 3.71 3.58   The scatter diagram for the SAT score and GPA is given below:   (a)  Find the sample correlation coefficient r.  Truncate to two decimal places.  What does the value tell you about the data? (b)  Find the equation of the least squares line .  Truncate to four decimal places.  What does the slope mean? (c)  Find the value of the coefficient of determination .  Truncate to two decimal places.  What does this number mean? (d)  What is the predicted GPA if a computer science major got a…

Historically it has been observed that patients admitted to a certain hospital for treatment of influenza spend a MEAN length of 4.4 days in the hospital. Every flu season, different strains of the flu circulate: Some years the primary strain causes more severe illness (and presumably longer than average hospital stays) and other years less so (meaning presumably shorter than average stays). We assume the hospital stays are NORMALLY distributed. a. A hospital wants to see how this year's flu season compares to previous years. Therefore, state the null and alternate hypotheses that would be used to test whether the hospital is seeing a mean hospital stay that is significantly DIFFERENT than the historical mean of 4.4 days. b. FIFTEEN patients admitted for influenza treatment are then randomly sampled and the length of their hospital stay in days is given below. 4641056443743774 SAMPLE MEAN =? SAMPLE STANDARD DEVIATION =? c. Using the results of part (b), determine what type of test is…

Listed below are amounts of arsenic in samples of brown rice from three different states. The amounts are in micrograms of arsenic and all samples have the same serving size. The data are from the Food and Drug Administration. Use a 0.05 significance level to test the claim that the three samples are from populations with the same mean. Assume that the  distributions for each state are normal and that all variances are equal.   Arkansas       4.8    4.9   5.0     5.4   5.4    5.4    5.6    5.6   5.6   5.9   6.0    6.1 California.     1.5     3.7    4.0    4.5   4.9    5.1     5.3    5.4   5.4   5.5   5.6    5.6 Texas.           5.6     5.8    6.6    6.9.  6.9    6.9    7.1     7.3    7.5    7.6   7.7     7.7

A sample of the monthly amounts spent for food by families of four receiving food stamps approximates a symmetrical distribution. The sample mean is $150 and the variance is $400. Using the Empirical Rule, about 95 percent of the monthly food expenditures are between what two amounts? Select one: $85 and $105 Ob. $205 and $220 O $110 and $190 Od. $100 and $200